1. Field of the Invention
The present invention relates to a microchip useful as μ-TAS (Micro Total Analysis System) suitably used for biochemical test for DNA, protein, cell, immunity, or blood, chemical synthesis, or environmental analysis. In particular, the present invention relates to a liquid reagent containing microchip in which a liquid reagent to be mixed or reacted with a sample to be tested or analyzed is contained in advance in a reagent retaining portion in the microchip.
2. Description of the Background Art
In recent years, in the fields of medical care, health, food, drug discovery, and the like, detection or quantitation of biological substances such as DNA, enzyme, antigen, antibody, protein, virus, and cell as well as chemical substances has become increasingly important, and various biochips and micro chemical chips (such chips will hereinafter be collectively referred to as microchip) with which the above-described substances can be easily and conveniently measured have been proposed.
The microchip can be used to allow a series of experimental and analytical operations, which are usually performed in a laboratory, to be conducted within the small chip. The microchip accordingly provides many advantages that the amounts of samples and liquid reagents to be used are very small, the cost is low, the reaction rate is high, high throughput test or analysis can be conducted, and the test results can be immediately obtained at the site where the sample was taken, for example.
A known microchip includes a flow path network, called a “fluid circuit” (or “micro fluid circuit”), which is constituted of different kinds of parts (chambers) for performing particular treatments on a sample or liquid such as a liquid reagent present in the circuit, and minute flow paths appropriately connecting these parts (for example, see Japanese Patent Laying-Open No. 2007-285792). In a test or analysis of a sample using the microchip including such a fluid circuit therein, the fluid circuit is used to perform various treatments including measurement of a sample introduced in the fluid circuit (or a specific component in the sample) and a liquid reagent to be mixed with the sample (that is, transfer to a measuring portion that is a part for performing measurement), mixing of the sample (or a specific component in the sample) with the liquid reagent (that is, transfer to a mixing portion that is a part for mixing the sample and the liquid reagent), and transfer from one part to another part.
It is noted that treatments of various liquids (such as a sample, a specific component in the sample, a liquid reagent, or a mixture of two or more kinds thereof) performed in the microchip will hereinafter sometimes be referred to as “fluid treatment”. These various fluid treatments can be performed by applying centrifugal force in an appropriate direction to the microchip.
Of the microchips as described above, a liquid reagent containing microchip is a microchip in which a liquid reagent to be mixed or reacted with a sample or a specific component in the sample is retained in advance in the fluid circuit. One or more reagent retaining portions that accommodate the liquid reagent are provided in the fluid circuit of the liquid reagent containing microchip. In the liquid reagent containing microchip, a reagent inlet for pouring the liquid reagent into the reagent retaining portion is generally provided on one surface of the microchip so as to reach the reagent retaining portion.